Vertical mold press for molding articles of rubber-like material

ABSTRACT

A press for molding articles such as O-rings of rubber-like material characterized in that a pair of vertically disposed mold plates secured to heating platens are relatively horizontally movable into and out of mating engagement, the press, when open, being unloaded by gravity upon movement of a stripper downwardly between said mold plates, and being loaded by lateral movement of a vertical loading device to position uncured stock between said mold plates so that when the press is closed the stock is squeezed into the cavities in the mating faces of said mold plates. The press herein is further characterized in that when said mold plates are in mating engagement to cure the articles therein by heat and pressure the loading device may be withdrawn and moved to a horizontal position for loading of uncured stock thereon, the stock preferably being in the form of slit strips stretched over pins on the loading device. Yet another characterizing feature of this invention is that novel lock means are provided to releasably lock one mold plate (or both) to the respective heating platen, said lock means including wedge blocks which are adapted to be struck by hammer blows to lock or unlock the mold plate to or from the respective heating platen.

United States Patent n91 McCullough et al. 1451 Jan. 2, 1973 [54]VERTICAL MOLD PRESS FOR Primary Examiner-J. Howard Flint, Jr;

MOLDING ARTICLES OF RUBBER- Attorney-Oberlin, Maky, Donnelly & RennerLIKE MATERIAL [75] Inventors: Harry J. McCullough; John M [57] ABSTRACT1 Shahid, both of Lexington; Aland A press for molding articles such asO-rings of rubber- Boyd, Clay City, all of Ky. likematerial'characterized in that a pair of vertically [73] AssigneezParker Hamlin Corpora'fim disposed mold plates secured'to heatingplatens are Cleveland Ohio 7 g v relatively hor1zontally movable intoand out of mating engagement, the press, when open, being unloaded byFiled: y 10, 1971 gravity upon movement of a stripper downwardly [211App. NOJ 141,620 between said mold plates, and being loaded by lateralmovement of a vertical loading device to position uncured stock betweensaid mold plates so that when the [52] US. Cl. ..425/235, 425/28,425/383, press is closed the stock is squeezed into the cavities425/384, 425,395, 425,397 in the mating faces of said mold plates. 51Int. Cl. ..B29f 5/00v 53 i ld f Search 425]2 3 3 3 4 39 5 397 The pressherein is further characterized in that when 425 42 1 47 said moldplates are in mating engagement to cure the articles therein by heat andpressure the loading [56] References Cit d device may be withdrawn andmoved to a horizontal position for loading of uncured stock thereon, theUNTTED STATES PATENTS stock preferably being in the form of slit strips2,354,241 7/1944 Anderson ..425/235 1 Stretched P the wading device-2,646,595 7/1953 Leistenswider ..425/DIG, 47 2,798,257 7/1957 Beare..425/o1o. 47 I 1 i czaractemmg ig a '5 2,839,014 6/1958 Fine ..425/3s3x a means are e re y 9 2,943,354- 7/1960 Gora ..425'/D1G. 42 Plate (0r90th) the respective heating 2,962,761 12/1960 Hobson ..425/DlG. 47,platen, Said lock means including Wedge blocks which 2,976,575 3/1961Daubenberger ..425/DlG. 47 are adapted to be struck by hammer blows .tolock or 3,269,695 8/1966 Grove ..425/DIG. 47 unlock the mold plate to orfrom the respective heat- 3,195,180 7/1969 Jagger et al ..425/DIG. 42. it' 3,406,430 10/1968 Furstenburg et al ..425/D[G. 42

14 Claims, 6 Drawing Figures PATENTED AN 2 7 INVENTORS.

HARRY J MCCULLOUGH JOHN SHAH/D ALA/VD BOYD VERTICAL MOLD PRESS FORMOLDING ARTICLES OF RUBBER-LIKE MATERIAL BACKGROUND OF THE INVENTION Itis known in the art of molding articles such as rings from rubber-likematerial to insert one or more molds between relatively verticallymovably mounted press heads which have heating platens thereon, saidmolds generally comprising hinged together top and bottom mold platesbetween which uncured sheet or ring stock is loaded. In such presseswhen the curing cycle has been concluded the press heads are separatedand the molds are bodily removed from the press and opened to strip themolded articles therefrom followed by placement of uncured sheet or ringstock on the bottom mold plates. The molds are then closed andreinserted between the press heads to cure the stock in the moldcavities under heat and pressure. As apparent, when the molds arewithdrawn from between the heating platens there is opportunity forcooling thereof, whereby after the molds have been stripped, reloaded,closed, and reinserted in the press, the molds must be reheated toeffect proper curing of articles therein.

It has also been proposed heretofore to provide a press having duplicatetop mold plates in which the molded articles remain after the curingcycle. In such press when it is opened, one top plate with the moldedarticles therein is withdrawn horizontally and swung up to a verticalposition and thence moved to the side. Uncured stock is then placed onthe exposed bottom mold plate and the other top mold plate is insertedinto the press, the press then being closed, and while closed, themolded articles are stripped from said one top mold plate. It is alsoknown to provide such press in which the bottom mold plate with moldedarticles therein is withdrawn and inverted for stripping of the moldedarticles therefrom followed by turning it back to its normal positionfor loading of stock thereon and for reinsertion beneath a complementaltop mold plate. Here again, the removed mold plate has opportunity tocool and must be reheated to curing temperature.

SUMMARY OF THE INVENTION In contradistinction to known presses formolding articles of rubber-like material, the press constituting thepresent invention has vertically disposed mold plates which are securedto vertical heating platens and which, when the press is open,facilitates stripping of molded articles therefrom by gravity uponmovement of a stripper downwardly between the separated mold plates.

The press herein is further characterized in that it has a loadingdevice which while the press is closed during the mold plates. When thepress is closed, the stock is squeezed between the mold plates and ispinched off at the upper and lower edges of the mold plates so that theloading device may be withdrawn and moved to horizontal position forremoval of the pinched off stock from the pins for re-use and forloading with slit strips as aforesaid.

The press herein is further characterized in the provision of novel lockmeans for releasably locking one mold plate (or both) to the press, saidlock means preferably comprising wedge blocks which are drivendownwardly as by hammer blows to lock the mold plate to the press andwhich are driven upwardly and turned 180 to invert them so that theywill remain by gravity in mold plate releasing condition to facilitateremoval of the mold plate for servicing or replacement.

Other objects and advantages of the present invention will appearhereinafter.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a pressembodying the present invention;

FIG. 2 is a fragmentary perspective view showing the loading deviceready for lateral movement with respect to the fixed mold plate toposition the strips of uncured stock on said loading device directly infront of and in register with the cavities of said fixed mold plate;

FIG. 3 is a fragmentary elevation view showing the uncured stock on theloading device in register with the mold cavities of the fixed moldplate;

FIG. 4 is a fragmentary side elevation view showing the movable moldplate lock means in releasing position whereat the mold plate may bereadily removed or installed;

FIG. 5 is a fragmentary elevation view as viewed along the line 5-5,FIG. 4; and

FIG. 6 is a fragmentary side elevation view similar to FIG. 4 exceptillustrating the mold plate lock means in locking position.

DETAILED DESCRIPTION OF THE INVENTION As best shown in FIG. 1, the press1 herein comprises a base framework 2 as of angle iron to which issecured heavy vertical plates 3 and 4 with tie bars 5 extendingtherebetween to form a rigid box-like structure holding the plates 3 and4 parallel to each other with the bars 5 constituting guides for themovable press head 6. The plate 3 constitutes the fixed head of thepress to which is bolted or otherwise secured a heating platen 7 and amold plate 8. The movable head 6 of the press is lonthe curing cycle isdisposed in a horizontal position to facilitate loading of uncured stockthereon, such stock preferably being in the form of slit strips ofuncured rubber-like material which are stretched over pairs of verticalpins on the horizontally disposed loading device. When the press isopened and after stripping of the cured articles from the separated moldplates, the loaded loading device is moved to a vertical position and isthence slid laterally along guides of the fixed mold plate to positionthe uncured stock directly in front of the cavities in the latter, theloader pins being disposed above and below the upper and lower edges ofgitudinally movably guided along the bars 5 by concave rollers 9 and bylongitudinally extending guide shoes 10 for movement toward and awayfrom the fixed head 3, said movable head 6 having secured thereto aheating platen 11 and a mold plate 12. Said mold plates 8 and 12, whenengaged with each other, define mold cavities conforming to the articlesto be molded. By way of example, the cavities herein are O-ringcavitiesarranged in horizontal and vertical rows as shown, and the fixedmold plate 8 will be provided with further recesses or cavities withinthe respective O-ring cavities to accommodate excess material.

. The end plate 4 has secured thereto a hydraulic cylinder 14, thepiston rod l5 of which is connected to the center of the movable presshead 6 and adjustable gregate volume of the cavities defined when themold stop means 16 in the cylinder 14 is engaged by the piston thereinto determine the amount of opening movement of the press so that thedistance between the mold plates 8 and 12 is slightly lessthan the widthof the stripper ,17 which has opposite pairs of stripper blades ofrubber-like material to strip molded articles from the mold plates 8 and12 when the stripper 17 is moved downwardly between said mold plates 8and 12 as by means of an actuating cylinder 18 mounted on the bracket 19of the upright framemember 20. By reason of the provision of the excessmaterial cavities in'the fixed mold plate 8, the molded articles willgenerally remain stuck there. Movement of the stripper l7 downwardly andupwardly is guided as by means of the guide rods 21 thereon engaged inguide holes in the bracket 19. I

The platens 7 and 11 may be heated by any well known means such aselectrical heating elements (not shown) and at the end of the framework2 remote from the press actuating cylinder 14 there may be provided acontrol unit 23 which, if desired, may contain an'electtic motor drivenhydraulic pump and solenoid operated four-way valves which control thedirection of actuation of the respective cylinders 14 and 18. Thecontrolunit 23 may also be provided with an adjustable timer to retainthe press in closed position for the required curing time of the moldedarticles, temperature control means for adjusting the platen and moldplate temperatures, and such other controls as are generally employedwith molding presses for molding rubber-like articles.

A loading device 25 is supported on the shelf 26 of the framework 2 in ahorizontal position as shown in FIG. 1 sothat slit strips S of uncuredrubber-like material may be stretched over the upstanding pins 27 ofsaid loading device 25. The side rails 28 of the loading device 25 areof L-shaped cross-section complemental with the L-shaped slots 29through the fixed mold plate 8, the loading device 25 being supportedfor rotation from the horizontal position of FIG. 1 to the verticalposition of FIG. 2 and for sliding laterally of the mold plate 8 withthe rails 28 slidably engaged in the guide slots 29 by means of theelongated guide member 30 in which the support bar 31 of the loadingdevice 25 is rotatable and longitudinally slidable.

When the press is open as in FIG. 1, the loading device 25 with thestrips S mounted on pins 27 is swung from the horizontal position shownin FIG. 1 to the vertical position shown in FIG. 2, whereupon theloading device 25 is moved horizontally toward the fixed'mold plate8'with the L-shaped rails'28 engaged in the L- shaped guide slots 29 ofthe mold plate 8 thus to position the strips S inclose proximity to theface of mold plate 8 with the opposite sides of each strip S alignedwith the respective vertical rows of cavities as shown in FIG. 3. Thevolume of uncured stock exceeds the agplates 8 and 12 are in matingengagement. With the loading device 25 positioned-as shown in FIG. 3,the press actuating cylinder 14 may be actuated toward the right asviewed in FIG. 1, to squeeze the uncured stock strips S between the moldplates 8 and 12 in accurate registry with thecavities and to bite offthe portions of the strips S beyond the upper and lower edges of themold plates8 and 12 so that the loading device 25 may be withdrawntogether with the remaining bit-off pieces of stock S and swung to theFIG. 1 position. After such pieces have been removed from the pins 27,the loading device 25 may be reloaded with uncured'stock strips S duringthe time that the stockin the mold cavities is being cured underpressure and heat.

After a predetermined curing time which may be set by an adjustabletim'er not shown, a four-way solenoid valve for the press actuatingcylinder will be energized to admit fluid under pressure into the rodend of the cylinder 14 thus to move the head 6 to the left as viewed inFIG. 1, to an open position and if desired, at the time the adjustablestop 16 is engaged by the piston in cylinder 14 a limit switch may betripped to energize a four-way solenoid valve to cause the stripperactuating cylinder 18 to move the stripper 17 down for stripping themolded articles from the mold plates 8 and 12 for gravity discharge intoa suitable receptacle 32 positioned beneath the mold plates 8 and 12.When the stripper 17 reaches the lower end of its stroke, a limit switchmay be tripped thereby to reverse the solenoid valve therefor to movethe stripper 17 to its upper retracted position as shown in FIG. 1. r

The loader guide 30 may be provided with an adjustable stop 34 and limitswitch 35 which, when the loading device 25 is in proper position withthe uncured stock strips S properly aligned with the cavities of themold plates 8 and 12 the solenoid valve for the cylinder 14 will beenergized to move the press head 6 to closed position to grip the stockS between the mold plates 8 and 12 and to apply pressure thereon tocause it to flow into the mold cavities where it is cured under heat andpressure. v I In order to facilitate mold plate removal and assembly andmold plate alignment, the mold plate 12 is provided with keyhole slots36 to fit over the bolt heads 37 as shown in FIGS. 4 and 5, the bolts 38extending through holes in the heating platen 11 and having screwedthereon nuts 39 having inclined inner faces which cooperate withinclined faces of the wedge blocks 40. When the mold locking mechanismsare in the position shown in FIGS. 4 and 5 the mold plate 12 may belifted and withdrawn away from the heating platen 11 and replaced byanother mold plate having a like keyhole slot 36 construction at itsfour come'rs, the new mold plate being moved to the left as viewed inFIG. 4 and thence downwardly whereby the new mold plate is supported inapproximately aligned position with the fixed mold plate 8.

With the mold plate 12 thus suspended by the bolts .38, the cylinder 14may be actuated with low pressure to move the mold plate 12 into contactwith the fixed mold plate 8 and in this condition the mold plate 12 maybe shifted upward or sideward or tilted so as to be in perfect alignmentwith the fixed mold plate 8. With the mold plate thus held by frictionin aligned position, the wedge blocks 40 may be turned to the FIG. 6position and then struck downwardly as with a hammer to the lockingposition to secure tight clampingof the mold plate l2 to the platen ll-. g

-When it is desired to replace the mold plate 12 it is a simple matterto hit the wedgefblocks 40 upwardly to loosen themold plate 12 and thento turn the wedge blocks 40 backto the FIG. 4"position in'which theyhang by gravity to permit removal of the mold plate 12 by lifting andaxial movement.

The ends of the strips S which are bitten off during the press closingoperation may be saved and reprocessed to make new slit strips S. Ofcourse, when 'the uncured stock S is squeezed between the mold plates 8and 12 the adjoining strips S may be joined together as flash andtherefore the vertical rows of molded articles may be tied together as asingle sheet and will be stripped in that form into the receptacle 32.

-As aforesaid, the stock supporting pins 27 will be spaced apartsomewhat more than the length of the slit in each strip S so that inloading the loading device 25 the stock S will be stretched straightbetween the respective pairs of pins 27 in predetermined spaced apartrelation as determined by the diameters of the pins 25, so as to alignthe sides of the strips S with the respective vertical rows of cavities.The use of the press 1 herein for molding O-rings or the like is to beconsidered merely exemplary and it is apparent that the molded articleor articles may be of any desired shape just so long as the volume ofthe uncured stock exceeds the volume of the cavity or cavities definedbetween the mating mold plates '8 and 12 to insure complete filling ofthe cavity or cavities.

We, therefore, particularly point out and distinctly claim as ourinvention:

1. In a press of the type having relatively movable press heads withmold plates thereon which, when the press is closed, are in matingengagement to define therebetween a mold cavity in which an article ofrubber-like material is adapted to be formed and which, when the pressis open, are separated for removal of the molded article fromtherebetween, the improvement which comprises a loading device havingmeans to support molding stock thereon; guide means on said press toguide said loading device for lateral movement into and out of the pressrespectively to position the molding stock thereon between said moldplates when the press is open for squeezing of the stock into suchcavity as the press is closed and to withdraw said loading device forreloading with molding stock while the press is closed.

2. The press of claim 1 wherein stripping means is supported by saidpress for lateral movement into and out of the open press to engage themolded article to strip it from a mold plate in which it may be stuck.

3. The press of claim 1 wherein said loading device supports the moldingstock in close proximity to the molding face of one of said mold platesand beyond the opposite edges of the molding faces of said mold plateswhereby the molding stock is retained in predetermined position relativeto the mold cavity as the press is closed until the edges of saidmolding faces pinch off the molding stock therebeyond. 4. The press ofclaim 1 wherein said press heads include heating platens to which saidmold plates are secured to cure a rubber-like article under heat andpressure when the press is closed.

5. The press of claim 1 wherein said press heads and mold plates arevertically disposed for relative horizontal movement; wherein saidloading device supports the molding stock in vertical position; andwherein said guide means supports said loading device for horizontallateral movement in a vertical plane to position the molding stockvertically between said mold plates when the press is open.

loading device comprises upper and lower rows of transversely projectingpins over which slit strips of molding stock are positioned, said stripsof molding stock registering with said vertical rows of cavities whensaid loading device is moved into saidpress.

8. The press of claim 7 wherein said upper and lower rows of pins aredisposed above and below the upper and lower edges of the molding facesof said mold plates and are located to position the strips of moldingstock thereon in close proximity to the molding face of one of said moldplates whereby-said molding strips are held in position during theclosing of the press and until the portions of the strips above andbelow the molding faces is I pinched 'off 'upon closing of the presswhereafter the loading device may be withdrawn from the press forremoval of the pinched off portions of the strips from said pins and forreloading of molding stock strips onto said pins as aforesaid while thepress is closed. I

9. The press of claim 8 wherein said loading device, when withdrawn fromthe press, is supported by the press for movement to a horizontalposition'with said rows of pins extending upwardly to facilitate loadingmolding stock strips thereonto in horizontal position.

10. The press of claim. 9 wherein said rows-of pins are spaced apart adistance exceeding the length of the slits in said molding stock stripswhereby the latter are stretched oversaid pins to maintain them in aplane parallel to the molding faces-of said mold plates when saidloading device is moved back to vertical position preparatory tomovement into the open press.

11. The press of claim 5 wherein stripping means is supported by saidpress for vertical movement into and out of the open press to engage themolded article during downward movement of said stripping means to stripthe article from a mold plate in which it may be stuck for gravitydischarge from between the separated mold plates.

12. The press of claim 1 wherein one mold plate is secured to therespective press head by releasable lock means which includes a, boltand nut means and -a wedge block between said press head and said nutmeans .which. is adapted to be driven in opposite directions laterallyof said bolt means to lock and unlock said moldplate to or from saidpress head.

13. The press of claim 12 wherein said wedge block has en elongated slotthrough which'said bolt means lock means is in unlocking position, saidmold plate may be 'aised to position the large portion of the keyholeslot in regist:y with said bolt head for horizontal withdrawal movementof the mold plate with respect to said press head.

1. In a press of the type having relatively movable press heads withmold plates thereon which, when the press is closed, are in matingengagement to define therebetween a mold cavity in which an article ofrubber-like material is adapted to be formed and which, when the pressis open, are separated for removal of the molded article fromtherebetween, the improvement which comprises a loading device havingmeans to support molding stock thereon; guide means on said press toguide said loading device for lateral movement into and out of the pressrespectively to position the molding stock thereon between said moldplates when the press is open for squeezing of the stock into suchcavity as the press is closed and to withdraw said loading device forreloading with molding stock while the press is closed.
 2. The press ofclaim 1 wherein stripping means is supported by said press for lateralmovement into and out of the open press to engage the molded article tostrip it from a mold plate in which it may be stuck.
 3. The press ofclaim 1 wherein said loading device supports the molding stock in closeproximity to the molding face of one of said mold plates and beyond theopposite edges of the molding faces of said mold plates whereby themolding stock is retained in predetermined position relative to the moldcavity as the press is closed until the edges of said molding facespinch off the molding stock therebeyond.
 4. The press of claim 1 whereinsaid press heads include heating platens to which said mold plates aresecured to cure a rubber-like article under heat and pressure when thepress is closed.
 5. The press of claim 1 wherein said press heads andmold plates are vertically disposed for relative horizontal movement;wherein said loading device supports the molding stock in verticalposition; and wherein said guide means supports said loading device forhorizontal lateral movement in a vertical plane to position the moldingstock vertically between said mold plates when the press is open.
 6. Thepress of claim 5 wherein said loading device, when withdrawn from saidpress, is supported by the latter for movement to a horizontal positionto facilitate loading of molding stock thereonto in horizontal positionwhile the press is closed.
 7. The press of claim 5 wherein said moldcavity comprises a plurality of cavities arranged in vertical rows; andwherein said stock support means of said loading device comprises upperand lower rows of transversely projecting pins over which slit strips ofmolding stock are positioned, said strips of molding stock registeringwith said vertical rows of cavities when said loading device is movedinto said press.
 8. The press of claim 7 wherein said upper and lowerrows of pins are disposed above and below the upper and lower edges ofthe molding faces of said mold plates and are located to position thestrips of molding stock thereon in close proximity to the molding faceof one of said mold plates whereby said molding strips are held inposition during the closing of the press and until the portions of thestrips above and below the molding faces is pinched off upon closing ofthe press whereafter the loading device may be withdrawn from the pressfor removal of thE pinched off portions of the strips from said pins andfor reloading of molding stock strips onto said pins as aforesaid whilethe press is closed.
 9. The press of claim 8 wherein said loadingdevice, when withdrawn from the press, is supported by the press formovement to a horizontal position with said rows of pins extendingupwardly to facilitate loading molding stock strips thereonto inhorizontal position.
 10. The press of claim 9 wherein said rows of pinsare spaced apart a distance exceeding the length of the slits in saidmolding stock strips whereby the latter are stretched over said pins tomaintain them in a plane parallel to the molding faces of said moldplates when said loading device is moved back to vertical positionpreparatory to movement into the open press.
 11. The press of claim 5wherein stripping means is supported by said press for vertical movementinto and out of the open press to engage the molded article duringdownward movement of said stripping means to strip the article from amold plate in which it may be stuck for gravity discharge from betweenthe separated mold plates.
 12. The press of claim 1 wherein one moldplate is secured to the respective press head by releasable lock meanswhich includes a bolt and nut means and a wedge block between said presshead and said nut means which is adapted to be driven in oppositedirections laterally of said bolt means to lock and unlock said moldplate to or from said press head.
 13. The press of claim 12 wherein saidwedge block has en elongated slot through which said bolt means passes,said mold plate and press head being disposed in vertical position withsaid bolt and nut means disposed horizontally whereby said wedge blockis adapted to be driven downwardly to locking position and upwardly tounlocking position, said wedge block, when in unlocking position, beingturned 180* to retain it by gravity in such unlocking position.
 14. Thepress of claim 13 wherein said mold plate has a keyhole slottherethrough through the wide portion of which the head of said boltpasses whereby, when said lock means is in unlocking position, said moldplate may be raised to position the large portion of the keyhole slot inregistry with said bolt head for horizontal withdrawal movement of themold plate with respect to said press head.